JPS63223367A - Controller for hydroelectric generating installation - Google Patents

Abstract

PURPOSE:To make such operation that turbine efficiency comes to the maximum as well as high speed AFC (automatic frequency control)operation performable, by regulating guide vane opening of a hydraulic turbine and revolving speed of the turbine to the given turbine's operating head and the target generator output. CONSTITUTION:A time of AFC operation, guide vane target opening (a)* is found out of an operating head H of a hydraulic turbine 2 and the target genera tor output P* at that time by a opening setter 5. And, a guide vane 3 is con trolled by a guide vane controller 6 in accordance with a deviation DELTAa between this target opening (a)* and the guide vane actual opening (a). And, on the basis of the head H and the actual opening (a), target turbine revolving speed N* is calculated by a speed setter 7, the opening deviation DELTAa is compared with the preset judged value by a judger 8, and when a side of the opening deviation DELTAa is larger or smaller, a transfer 9 is selected to a contact A or B, and a generator 1 is controlled via a speed changer 4 according to an output deviation DELTAP(=P*-P or a speed deviation N(=N*-N).

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention is directed to the control of hydroelectric power generation equipment that has a water turbine capable of variable speed operation and a generator connected thereto. Regarding equipment.

(Prior Art) In general, hydroelectric power generation equipment may be operated in such a way that the output of the power plant is varied over time based on an output command in order to stabilize and adjust the power system. This type of operation is called AFC (automatic frequency control) operation, and in the case of conventional power generation equipment that has a water turbine connected to a synchronous generator and operated at a constant rotation speed, the water turbine is guided based on the output command. This has been done by adjusting the vane opening.

FIG. 8 is a time chart for explaining such a conventional control device for hydroelectric power generation equipment. In the figure, (a) shows the load fluctuation, (b) shows the guide vane opening degree, (c) shows the water pressure in the penstock, and (d) shows the rotation speed of the main generator.

As shown in the figure, when the load fluctuates, the guide vane opening changes in order to keep the rotational speed of the main generator constant. However, when the load fluctuation period f is short and the load fluctuation width ΔP is large, if the opening and closing speed of the guide vanes is fast, the water hammer effect caused by the change in the flow rate of the turbine may induce surging in the pipeline system, or damage the inlet side of the turbine. There is a risk that excessive pressure fluctuations may occur in the water pressure of iron pipes. For this reason, in a water turbine operated at a constant rotational speed, the 1" product output changes rapidly at high speed A.
FC operation was almost impossible.

On the other hand, as a recent trend, hydroelectric power generation equipment that uses a wound induction generator instead of a synchronous generator and is capable of variable speed operation has been adopted. In such a water turbine capable of variable speed operation, by adjusting the amount of excitation of the wound induction generator, the generator output can be changed at high speed without changing the guide vane opening. In this case, since the guide vane opening degree does not change, the problem of the pipeline system due to the water hammer effect mentioned earlier is eliminated.
Therefore, high-speed AFC operation is possible.

However, even in hydroelectric power generation equipment capable of variable speed operation, high-speed AF can be achieved simply by adjusting the amount of excitation of the wound induction generator.
Various problems occur when performing C operation.

This point will be explained according to the time chart of FIG. The figure (a) shows the target generator output P*, the figure (b) shows the generator output P, the figure (c) shows the actual guide vane opening a, and the figure (d) shows the water turbine rotation speed N. The figure (e) shows the generator torque M and the water turbine torque M1, respectively.

First, consider the response of the low water turbine and generator when the target generator output P* increases stepwise from the value P* to the value P* at time t. Since the amount of excitation is adjusted instantaneously, the generator output Pg is the value P. Then, it immediately changes to match the target value. the result,
The generator torque M and the water turbine torque M are determined at time t. After that, since Mt becomes less Mg, the water turbine rotational speed N decreases. In other words, even if the rotational speed changes, no problem will occur in variable-speed controlled hydroelectric power generation equipment because the generator output is converted to a constant frequency of the grid using a thyrisk-type frequency converter (hereinafter referred to as a thyrisk converter).

However, the frequency that can be converted by a thyristor converter has an upper and lower limit depending on the capacity of the thyristor, so if there is too large a fluctuation in the output, the change in rotational speed will exceed the two or lower limits, making it difficult to control only the amount of excitation. Then, we will not be able to respond.

In the example shown in FIG. 9, at time t1, the water turbine rotational speed N approaches the lower limit rotational speed that can be converted by the thyristor, that is, N - N1, so an opening increase command is sent to the guide vane on this condition, and the After t1, the guide vane actual opening degree a increases.

As a result, the water turbine torque M1 increases rapidly and Ml>Mg at time t2, so the water turbine rotational speed N increases again. However, in such a situation, the opening degree of the guide vane must be changed, and even though the turbine is operated at variable speed, it is difficult to respond to the demand for sudden changes in output, even if the turbine is operated at variable speed. Due to system problems, it becomes impossible to follow.

If we look at the above response process in terms of water turbine characteristics, we can see the characteristic diagram in Figure 10. In other words, points Xo, Xt, X
A thick line connecting , indicates the locus of the operating point of the water turbine from time 10 to times t1 and t2.

Note that curve a1. a2 + a3. For a4, the guide vane actual opening degree a is al'a2'a3' a4.
It shows the relationship between the water turbine rotational speed N and the water turbine output P1 at the time of . Moreover, the broken line η1. η2. η3. η4 are each equal efficiency curves. On the other hand, curve k. is the maximum efficiency point at each guide vane opening.

As is clear from the figure, from time 10 to tl, the guide vane opening is constant and the water turbine rotational speed N decreases as shown. As the water turbine rotational speed N decreases, the water turbine output PL also increases, and this is shown by the increase in the water turbine torque Mt in FIG.

In Fig. 9, at time t1, the water turbine rotation speed N is N<N.
The operating point corresponding to point X1 in FIG. 10 corresponds to point X1. 1st
From Figure 0, for a water turbine capable of variable speed operation, the operating point is a curve k depending on the current water turbine output Pt and the actual guide vane opening degree a. It can be seen that by adjusting the rotational speed N so that it is above , the water turbine can always be operated at maximum efficiency. However, in a control method in which the output is adjusted by simply changing the excitation amount of the generator in response to a sudden change in the target generator output P*, the operating point moves away from the maximum efficiency point.

On the other hand, as shown in Japanese Patent Application Laid-Open No. 59-72998, both the guide vane actual opening a and the water turbine rotational speed N are changed in response to changes in the target generator output P*, so that the operating point is always curve k. It can also be controlled so that it comes to the top. However, according to this method, no matter how quickly the generator excitation amount is adjusted, -7 = generator output Pg does not change until the guide vane actual opening a changes, so the target generator output P*
The followability of the generator output P to the change in the guide vane actual opening degree a depends on the speed of change of the guide vane actual opening degree a. therefore,
In this case, as in the conventional constant-speed operation water turbine, even if the water turbine can be operated at variable speeds, there are problems with the pipeline system and poor follow-up to sudden requests for changes in the target generator output P'.

(Problems to be Solved by the Invention) As described above, in AFC operation in which the generator output P is changed over time, in a water turbine operated at a constant speed, sudden guidance is required in consideration of the water hammer effect of the pipeline system. Since the change in vane opening degree is restricted, it is not possible to follow high-speed AFC operation in which the target generator output P* changes rapidly.

On the other hand, in a water turbine operated at variable speed, by adjusting the amount of excitation of the wound induction generator, the generator output P can be changed at high speed without changing the opening of the guide vane of the water turbine.
High-speed AFC operation is possible. However, even in generators that operate at variable speeds, the range of rotational speeds that can be operated at variable speeds is limited by the capacity of the thyristor comparator. The change in the output power is out of the operable range, and it becomes impossible to respond to the change in the target generator output P* only by changing the excitation amount. In such a case, the actual guide vane opening a
It becomes necessary to adjust the output by changing the water wheel, but in this case, as in the case of a water turbine operated at a constant speed, it is no longer possible to adapt it to high-speed AFC operation due to the problem of water hammer in the pipeline system. Put it away. In other words, a water turbine operated at variable speed changes both the guide vane actual opening a and the water turbine rotational speed N with respect to the target generator output P*', so that the efficiency is maximized for the generator output P at that time. However, as mentioned above, the target generator output P*
If the amount of excitation is simply changed in response to changes in , the operating point will deviate from the maximum efficiency point.

By controlling both the water turbine rotational speed N and the actual guide vane opening a, the operating point can always be set to the highest efficiency point at that guide vane opening, no matter how the target output changes. However, in this case, the speed of change in output is equal to the speed of change in the guide vane, so high-speed AF is required, similar to a water turbine that operates at a constant rotation speed.
It will not be possible to support C operation.

Therefore, an object of the present invention is to solve the problems of the prior art described above, and to provide a high-speed AFC that changes the generator output at high speed in a hydroelectric power generation facility having a water turbine and a generator that are operated at variable speeds.
Hydroelectric power generation that enables high-efficiency operation by adjusting the guide vane opening and rotational speed of the water turbine to the given operating head and target generator output to maximize the efficiency of the water turbine. Our purpose is to provide equipment control devices.

[Structure of the invention]

(Means for Solving the Problems) The control device for hydroelectric power generation equipment of the present invention provides a first control system that calculates a target opening degree a* of a guide vane of a water turbine from a target output P* of a generator and an operating head H of a water turbine. a calculation means, and a first control means for controlling the actual guide vane opening a of the water turbine with a predetermined time constant based on the guide vane target opening a* calculated by the first calculation means; a second calculation means for calculating the optimum target water turbine rotation speed N* based on the operating head H of the water turbine and the actual guide vane opening degree a; and an optimum target water turbine rotation speed N1 calculated by the second calculation means; a third calculation means that calculates a speed deviation ΔN=N*−N by comparing the actual rotational speed N of the water turbine; and an output deviation Δ
A fourth calculation means calculates P=P*-P, and generates electricity so that the speed deviation ΔN calculated by the third calculation means and the output deviation ΔP calculated by the fourth calculation means are respectively zeroed. The present invention is characterized by comprising a second control means for controlling the machine.

(Function) The control device for hydroelectric power generation equipment of the present invention adjusts the output mainly by changing the guide vane opening degree in response to slow changes in the target output, and also adjusts the rotational speed of the water turbine when its operating point is high. Highly efficient operation is possible because it is controlled to be in the efficiency range. In addition, in response to a sudden change in the target generator output P*, the time constant set in the guide vane opening control means suppresses the sudden change in the actual guide vane opening a, and also controls the generator. By controlling the speed deviation ΔN and the output deviation ΔP by the means, high-speed responsiveness to the target generator output P* can be ensured.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of a control device for a hydroelectric power generation facility according to an embodiment of the present invention. As shown in the figure, the generator 1 is composed of a wire-wound induction machine, and is directly connected to the water turbine 2. The flow of water flowing into the water wheel 2 can be adjusted by means of guide vanes 3. The transmission device 4 adjusts the amount of excitation of the generator 1 so that a speed deviation ΔN or an output deviation ΔP, which will be described later, becomes zero, and controls the generator output P or rotational speed N. In AFC operation, based on the characteristics of the water turbine that are determined in advance by the opening setting device 5 from the operating head H of the water turbine at that time and the target generator output P*, the guide vane opening that is considered to be the best = 12 - is guided. Obtain the vane target opening a*. The guide vane controller 6 controls the guide vane 3 of the water turbine so that it matches the actual guide vane opening of the water turbine, that is, the actual guide vane opening a or the target guide vane opening a*.

However, since a sudden change in the guide vane actual opening degree a induces excessive pressure fluctuations, surging, etc. in the pipeline system due to the water hammer effect, the guide vane controller 6 operates as a first-order delay system with an appropriate time constant. No matter how rapidly the target vane opening a* changes, the actual guide vane opening a is controlled so as not to exceed a predetermined rate of change. The guide vane actual opening degree a and the operating head H are also input to the speed setter 7, and a target water turbine rotation speed N* that is considered to be optimal is calculated from the water turbine characteristics determined in advance. Difference between guide vane target opening a* and guide vane actual opening a, that is, opening deviation Δa=a*-a
and a predetermined judgment value ΔaO, and based on the comparison signal M, when Δa≧ΔaO, the switch 9 is switched to the contact A side, and when Δa - Δao, the switch 9 is switched to the contact A side. Switch to contact B side. The difference between the target water turbine rotation speed N* and the actual water turbine rotation speed N, that is, the speed deviation ΔN=N*-N, is input to the contact B of the switch 9, and the contact A is inputted to the contact B.
The difference between the target generator output P* and the actual generator output P, that is, the output deviation ΔP=P*−P is input. The mover of the switch 9 is guided to the transmission 4. Therefore, Δa
When ΔaO, the switch 9 is switched to the contact B side, and the generator 1 is controlled via the transmission 4 so that ΔN=0. Also, when Δa≧ΔaO, the switch 9 is connected to contact A.
The generator is switched to the side, and the generator is controlled via the transmission 4 so that ΔP=0.

In the device shown in FIG. 1, the target generator output P* is at time t
The response when changing from P* to P* in the second
This is shown in the time chart in the figure. The figure (a) shows the target generator output P*, the figure (b) shows the water turbine output P and the generator output Pg, and the figure (c) shows the guide vane target opening a* and the guide vane actual opening. (d) shows the contact position of the switching device 9, (e) shows the target water turbine rotation speed N* and water turbine rotation speed N, and (f) shows the water turbine torque M1 and generator torque M. are shown respectively.

Now, at time t, when the target generator output P* changes in a stepwise manner as shown in FIG. a* also changes instantaneously, as shown by the broken line in FIG. 4(c). However, since a guide vane controller 6 is interposed between the guide vane target opening a* and the guide vane actual opening a*, rapid changes in the guide vane target opening a* are alleviated, so that the guide vane The actual vane opening degree a changes only gradually, as shown by the solid line in FIG. Before time t, a=a*, that is, Δa=O, so it is on the contact B side of the switch 9, but at time t. Thereafter, a difference occurs between the guide vane target opening a* and the guide vane actual opening a, and Δa
≧Δao, and as shown at the contact point of the switch 9, the time t
. A little later, it switches to the A side. When the contact point of the switch 9 is switched to the A side, the difference between the target generator output P* and the actual generator output P, that is, the output deviation ΔP, is input to the variable speed device 4, and the output deviation ΔP is set to zero. The amount of excitation of the generator 1 is controlled. Since the response of the wire-wound induction generator and the thyristor converter is very fast, the output of the generator 1, that is, the generator output P 2 changes almost instantaneously, as shown in FIG. 4(b). On the other hand, since the opening degree of the guide vane 3, that is, the actual guide vane opening degree a, gradually increases from time 10 as shown in FIG. Changes to In this case, the water turbine I, the torque Mt, and the generator torque M change as shown in the figure (f), and between time t and tl, Mt - Mg, so the water turbine rotational speed N changes as shown in the figure (e). decreases as shown in . In this way, when the water turbine rotational speed N decreases and the guide vane actual opening degree a increases, the increase in the water turbine torque M exceeds the generator torque M at time 11, so from time t1 onwards, The water turbine rotation speed N increases. When the actual guide vane opening a further increases and at time t2 the difference from the guide vane target opening a*, that is, the opening deviation Δa, falls below the determination value ΔaO, the opening difference determiner 8 operates and the switch 9 The contact switches to the B side. As a result, in the subsequent control, the rotation speed of the generator 1 is controlled so that the water turbine rotation speed N matches the target water turbine rotation speed N*, and at time t3, the final target state is reached, that is, the generator ratio * Power P= P, water turbine rotation speed N=N1.

The characteristic diagram in FIG. 3 shows the changes in the operating point of the water turbine during the following control process. The same figure shows the 10th diagram used to explain the prior art.
This corresponds to the characteristic diagram in the figure.

As shown in FIG. 3, the operating point X is at time t. This corresponds to the operating point in . The operating point at which the speed N is the lowest at time t1 is point X. The final operating point at time t3 is point X1. In this way, the control device in this embodiment not only can respond immediately to sudden changes in target output, but also ultimately brings the operating point of the water turbine to the operating point at which the efficiency is highest, that is, on the line ko. be able to.

FIG. 4 is a time chart showing the response to a relatively slow change in the target generator output P*, and FIG. 5 is a time chart showing the response to a relatively rapid change in the target generator output P*. In each figure, (a) is the target generator output P
*, (b) is the generator output P, (c) is the guide vane target opening a zero and the guide vane actual opening a, (d)
indicates the switching position of the switching device 9, and (e) indicates the target water turbine rotation speed N.
* and water turbine rotational speed N, respectively.

Figure 4 shows the response to a slow change in the target generator output P*. In this case, since the target generator output P zero changes slowly, the guide vane target opening a* and the guide vane actual opening There is almost no difference from a, that is, an opening deviation. As a result, since the contact point of the switching device 9 in FIG. In order to control the water turbine rotation speed N to zero, the operating point at that time is line k in Fig. 3. It changes with the characteristics shown by. That is, in this case, the water turbine rotational speed N is only slightly adjusted to reach the highest efficiency condition at each output. Note that the generator output Pg is mainly adjusted only by changing the guide vane opening degree.

On the other hand, the case of FIG. 5 shows the response to a rapid change in the target generator output P*. In this case, since the target generator output P* changes greatly and quickly, the difference between the guide vane target opening a* and the guide vane actual opening a becomes large, and Δ
a≧ΔaO. As a result, the switching device 9 is switched to the contact A side via the opening degree determination device 8. Since the guide vane target opening degree a* changes periodically, at a certain moment it will not be as shown in Figure 5 (c
), the characteristic lines of the target opening a* and the actual opening a intersect. In other words, guide vane target opening degree a*=
Since the point where the guide vane actual opening degree a appears periodically,
At that moment, the switch 9 is switched to the contact B side, but at other times, the switch 9 is switched to the contact A side, and the generator 1 The amount of excitation is adjusted. As a result, the target generator output P
Although the change in * is fast and large, the actual generator mill force P can be made to approximately follow the target generator output P* as shown in the figure. As a result, a difference occurs between the generator torque M 1 and the water turbine torque M1, so the water turbine rotational speed N changes as shown in the figure in accordance with the unbalanced torque. On the other hand, the guide vane actual opening a is the guide vane target opening a
Even though * changes greatly as shown, the change is moderated by the guide vane controller 6, so the movement is not so large. For this reason, even though the change in the generator output Pg is large and fast, the actual guide vane opening a
Since there is little change in , pressure fluctuations and surging in the pipeline system can be suppressed to a non-problematic level.

As described above, according to this embodiment, in the variable speed control hydroelectric power generation equipment, high-efficiency operation can be performed in response to a request for slow AFC operation, and operation with high responsiveness can be performed in response to a request for high-speed AFC operation. It becomes possible.

FIG. 6 is a block diagram of a control device for a hydroelectric power generation facility according to another embodiment of the present invention. The difference from the configuration shown in FIG. This means that a control signal is given to the transmission 4. In the figure, the first variable gain amplifier 10 and the second variable gain amplifier 11 have the function of changing the gain according to the opening deviation Δa between the guide vane target opening a* and the guide vane actual opening 8, and 1
The second variable gain amplifier 10 multiplies the output deviation ΔP between the target generator output P* and the generator output P by a gain G1 corresponding to the opening difference Δa and sends it out as G1·ΔP. The speed deviation ΔN between the target water turbine rotation speed N1 and the water turbine rotation speed N is multiplied by a gain G2 corresponding to the opening difference Δa and sent as G2·ΔN. Here, by setting the gain G1 of the first variable gain amplifier [0] and the gain G2 of the second variable gain amplifier 11 as shown in FIG. 7, the switch 9 of FIG. A corresponding function can be realized.

As shown in FIG. 7, the gain G of the first variable gain amplifier 10 is approximately zero in the range of 1Δa1 minus 1Δaol, and the gain G2 of the second variable gain amplifier 11 is approximately zero in the range of 1Δa1≧IΔaol. As a result, the signal input to the transmission 4 becomes a speed deviation ΔN in the range of lΔa1 minus 1Δaol, and becomes an output deviation ΔP in the range of 1Δa1≧1Δaol.

In addition, 1. Gain G1 of the second variable gain amplifier 10°11. G2 is not limited to the characteristics shown in FIG. 7; for example, the change between "0" and "1" may be gradual, and the gain setting range may be set to "], 0" or more. You can also do this.

In each embodiment, adjustment is made by the switch 9 or the first variable gain amplifier 10 depending on the opening deviation Δa between the target generator output P* and the actual guide vane opening 8. As shown in FIG. 2, the value of the output deviation ΔP becomes a large value only when the target output P* changes rapidly, and is almost zero in other cases. Therefore, even if the output deviation ΔP is always input to the transmission 4, the state quantities shown in FIG. 2 do not change much. Therefore, in order to simplify the control system, substantially the same effect can be obtained even if the switch 9 or the first variable gain amplifier]0 is omitted.

〔Effect of the invention〕

According to the present invention, in the hydroelectric power generation equipment that is controlled by variable speed,
To enable high-speed AFC operation that changes generator output at high speed, and to adjust guide vane opening and water turbine rotation speed so that the turbine efficiency is highest for a given operating head and target generator output. Accordingly, it is possible to provide a control device for hydroelectric power generation equipment that enables highly efficient operation.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a control device for a hydroelectric power generation facility according to an embodiment of the present invention, FIG. 2 is a time chart for explaining the operation of the device in FIG. 1, and FIG. 3 is a block diagram of the device in FIG. 1. Figures 4 and 5 are operational characteristic diagrams for explaining the operational characteristics of
The figure is a time chart for explaining the operation when the change in target generator output is slow and rapid in the apparatus shown in Fig. 1, and Fig. 6 is a control of hydroelectric power generation equipment according to another embodiment of the present invention. A block diagram of the device, FIGS. 7(a) and 7(b) are gain characteristic diagrams of the first and second variable gain amplifiers in the device of FIG. 6, and FIG. 8 explains the control concept of conventional hydroelectric power generation equipment. Figure 9 is a time chart for explaining the concept of high-speed AFC operation of conventional hydroelectric power generation equipment, and Figure 10 is a time chart for explaining the operating characteristics of high-speed AFC operation of conventional hydroelectric power generation equipment. It is a driving characteristic diagram. DESCRIPTION OF SYMBOLS 1... Generator, 2... Water turbine, 3... Guide vane, 4... Transmission device, 5... Opening degree setting device, 6... Guide vane controller, 7... Rotation Speed setting device, 8...
Opening difference determiner, 9...Switcher, 10.11...Variable gain amplifier. Applicant's agent Mr. Sato = 24 - Figure 1 Figure 7

Claims (1)

[Scope of Claims] 1. A control device for hydroelectric power generation equipment that controls a hydroelectric power generation equipment in which a generator is connected to a water wheel whose rotational speed can be set to any value within a predetermined range, comprising: a first calculation means for calculating a guide vane target opening degree a^* of the water turbine from a target output P^* of the water turbine and an operating head H of the water turbine; a first control means for controlling the guide vane actual opening degree a of the water turbine with a predetermined time constant based on the water turbine operating head H and the guide vane actual opening degree a; Optimal target water turbine rotation speed N^*
and a third calculation means that calculates a speed deviation ΔN by comparing the optimum target water turbine rotation speed N^* calculated by the second calculation means with the water turbine actual rotation speed N. a fourth calculating means for calculating an output deviation ΔP by comparing the target output P^* of the generator with the actual generator output P_g; and a speed deviation ΔN calculated by the third calculating means and the fourth calculating means. and second control means for controlling the generator so as to make each of the output deviations ΔP calculated by the calculation means zero. 2. The first control means includes means for calculating the difference between the guide vane target opening degree a^* and the guide vane actual opening degree a as an opening degree deviation Δa, and a means for calculating the difference between the guide vane target opening degree a^* and the guide vane actual opening degree a, and a means for calculating the difference between the guide vane target opening degree a^* and the guide vane actual opening degree a, and a means for calculating the difference between the guide vane target opening degree a^* and the guide vane actual opening degree a, and a means for calculating the difference between the guide vane target opening degree a^* and the guide vane actual opening degree a, and a means for calculating the difference between the guide vane target opening degree a^* and the guide vane actual opening degree a, and and a selection means for controlling the output deviation ΔP to be zero when the opening deviation Δa exceeds a predetermined judgment value, and for controlling the speed deviation ΔN to be zero when the opening deviation Δa is within a predetermined judgment value. A control device for hydroelectric power generation equipment according to claim 1, characterized in that: 3. The control device for hydroelectric power generation equipment according to claim 1, wherein the first control means includes means for setting a control gain of the generator based on the opening degree deviation Δa. .